The present invention generally relates to optical disks, and particularly to an optical disk having a novel format and a method of recording information on the same. That is, the present invention relates to a technology suitable for the format specifications of the next-generation rewritable optical disks such as MO, ASMO, MD-DATA, DVD-RAM and PD.
Magnetooptical disks, such as ASMO (Advanced Storage Magnetooptical Disk) each have a storage capacity of 6 GB or more, and the user can freely write information on these disks. A typical one of these disks has record management areas provided along the innermost and outermost peripheries of the disk with respect to its radius direction (across the tracks), and a plurality of bands provided between those peripheries. The record management areas are sometimes called a lead-in area and a lead-out area. The outermost and innermost peripheries are assigned to the lead-in and lead-out areas or to the lead-out and lead-in areas, respectively. This assignment is selective and depends on the specifications to be used.
The record management areas are prepared for the recording and reproducing system for the whole disk, the positional information of data area (for example, replacement area information which will be described later) and the other management information (for example, security data), and they are used only by the manufacturers, or cannot be changed by the user. The management information has so far been redundantly recorded in the two innermost and outermost record management areas in order to increase the reliability, and further recorded typically doubly even in one record management area. As a result, one management information has been quadruply recorded in the innermost and outermost record management areas. The reason was that when a disk was corroded by rust, the innermost or outermost record management area was empirically often all disabled.
The user can make access to each band which is composed typically of a data area and a replacement area. The data area is a area in which the user records certain data. The replacement area has replacement blocks stored for defective blocks (sectors) present in the data area. Therefore, if the data area includes no defective block, no data is written in the replacement area. The addresses in the replacement area are written in the above-mentioned record management areas.
The ASMO has sectors of the same length in order to record each track at a substantially constant density. Since the length of the circumference (in the sector direction) increases as we go from the inner to outer periphery of the disk, the number of sectors per circumference increases as we go from the inner to outer periphery of the disk. Each band is conceptually composed of one data area and one replacement area corresponding thereto. As the methods of arranging the sectors (physical format), there are known three kinds of systems: CLV (Constant Linear Velocity), CAV (Constant Angular Velocity) and ZCAV (Zone Constant Angular Velocity). For example, in the CAV or ZCAV system, the revolution velocity (angular velocity) is substantially constant in the inner and outer peripheries, and the synchronizing clock frequency for recording and reproduction is changed. For the ASMO, a CLV system is employed in which the rotation velocity is changed, and the clock frequency is constant.
In the conventional ASMO, if a defective block is found present in the data area and replaced by the replacement area during recording, the optical head is required to move to the innermost or outermost record management area and write this information therein. However, since three different rotation rates are assigned to the innermost and outermost peripheries and the corresponding band, large power is necessary to control a driving motor to drive for the writing. In addition, since the optical head is forced to move from the corresponding band to the innermost or outermost record management area, it takes a time to access. Thus if, for example, music or images (for example, motion pictures) to be continuously recorded were recorded on the ASMO, the information was sometimes partially not recorded due to the necessary access time at the replacement time, and the recording operation was stopped at that time. This trouble was not peculiar to the CLV system. Even if the CATV or ZCAV system were employed, the optical head had to move to the innermost or outermost recording area at the replacement time, and thus similarly it took a long time to access.
Accordingly, it is a general object of the present invention to provide a novel and useful optical disk and method of recording information on the same with the above problems solved.
Specifically, it is an object of the invention to provide an optical disk and method of recording information on the same in which the necessary time for the replacement is made shorter than in the prior art so that music and images (for example, motion pictures) can be recorded without dropout of information.
It is another object of the invention to provide an optical disk and method of recording information on the same in which the power necessary for the replacement time can be decreased as compared with that in the prior art when the CLV system is employed for a physical format.
It is still another object of the invention to provide an optical disk and method of recording information on the same in which the reliability of the replacement information can be maintained high and/or improved.
According to a first aspect of the invention, there is provided an optical disk formatted to have a record management area in which management information can be stored and of which the contents cannot be rewritten by the user, a data area to which the user can make access, and a replacement area capable of providing replacement blocks for defective blocks that exist in the data area, the record management area being provided at three or more locations on the optical disk so that different contents of the management information can be respectively stored in the management areas located at the different places.
The conventional optical disk has two record management areas respectively provided along the innermost and outermost peripheries, the two management areas having stored therein the same information. The optical disk according to the first aspect of the invention provides a novel format in place of the conventional one. That is, the optical disk according to this aspect has three or more record management areas on the disk, and these management areas are capable of storing different management information depending on the locations at which the management areas are provided. Therefore, the contents of the management information can be divided into a plurality of different information and disposed in different places in order that the management information cannot be lost and that predetermined processes can be well conducted. The management information includes one to promote that, for example, the moving time of the head can be reduced in the record processing or replacement processing and that the number of times the revolution rate of the disk or the clock frequency is changed can be decreased. In an example of the optical disk according to this aspect of the invention, although the management information of at least two areas of the three or more record management areas are different, the management information of all the three management areas may be the same. For example, in another example of this aspect, during the recording processing only the central management area is accessed and updated in its contents, and after the recording operation ends and before the power is turned off the management information in the central management area is copied into the other management areas.
According to a second aspect of the invention, there is provided an optical disk according to the first aspect of the invention, wherein the management information stored in the record management areas has first management information including a recording system for the overall disk, and second management information including address information of both defective blocks and replacement blocks, and the record management areas have first management areas located along the innermost and outermost peripheries of the optical disk to store the first management information, and a second management area located between the innermost and outermost peripheries of the optical disk to store the second management information. Thus, in an optical disk according to this aspect, the management information is the separated, or first and second management information, the first management area and the second management area are separated, and the second management information is stored between the innermost and outermost peripheries. Since the optical head is usually located between the innermost and outermost peripheries when the second management information is accessed to, the moving time of the optical head can be reduced as compared with that in the conventional optical disk in which the second management information is stored along the innermost and outermost peripheries. The second management area may be provided in one place or in a plurality of places together with all data area between the innermost and outermost peripheries.
According to a third aspect of the invention, there is provided an optical disk according to the second aspect, further including a plurality of bands each including a data area and a replacement area, the second management area being provided in the band of the corresponding data area. Thus, in the optical disk according to this aspect, the second management area and the optical head to access it normally exist in the same band. As a result, the moving distance of the optical head can be further reduced.
According to a fourth aspect of the invention, there is provided an optical disk according to the second aspect, wherein the first management area can also store the second management information. Thus, the optical disk according to the fourth aspect can store the second management information redundantly in a plurality of, for example, three or more, places on the disk.
According to a fifth aspect of the invention, there is provided an optical disk formatted to have a record management area in which first management information including a recording system for the overall disk can be stored and of which the contents cannot be rewritten by the user, a data area to which the user can make access, and a replacement area capable of providing replacement blocks for defective blocks that exist in the data area, the record management area being provided along the innermost and outermost peripheries of the optical disk, part of the data area having stored therein second management information including address information of both the defective blocks and the replacement blocks for replacing the defective blocks. Thus, in the optical disk according to the fifth aspect, since the second management information and the optical head to access this information exist together in the same or adjacent areas, the moving distance of the optical head can be reduced more than that in the conventional optical disk. Although the second management information can be accessed by the user, it can be selectively processed on a software basis not to be changed.
According to a sixth aspect of the invention, there is provided a method of recording on an optical disk, comprising the steps of reading a first management area provided along the innermost and outermost peripheries of the optical disk between which a data area and a replacement area are also provided, said first management area having stored therein first management information including a recording system of the overall disk; reading a second management area provided between the innermost and outermost peripheries of the disk and having stored therein second management information including address information of both defective blocks and replacement blocks for replacing the defective blocks; and writing certain data in the data area and the replacement area of the optical disk on the basis of the second management area. The recording method according to the sixth aspect proposes a novel starting up process for reading the second management area located in the innermost and outermost peripheries at the starting up time before data is recorded in the data area and replacement area.
According to a seventh aspect of the invention, there is provided a method of recording on an optical disk, comprising the steps of writing certain data in a data area of the optical disk that has provided, between the innermost and outermost peripheries of the disk, the data area to which the user can make access, and a replacement area and provided, along the innermost and outermost peripheries, a first management area having stored therein first management information including a recording system for all the disk; writing the certain data in a replacement block of the replacement area of the optical disk when a defective block exists in the data area; and writing address information of both the defective block and the replacement block as second management information in a second management area located between the innermost and outermost peripheries. Thus, in the recording method according to the seventh aspect, the second management information is recorded in the second management area between the innermost and outermost peripheries at the replacement time.
According to an eighth aspect of the invention, there is provided a method according to the seventh aspect, wherein the step of writing in the second management area uses a different revolution rate of the disk from that in writing in the first management area. Thus, according to the eighth aspect, the number of times the revolution rate of the disk is changed at the replacement time can be reduced more than in the conventional optical disk.
According to a ninth aspect of the invention, there is provided a method according to the seventh aspect, wherein the step of writing in the second management area uses a different clock frequency from that in writing in the first management area. Thus, according to the ninth aspect, the number of times the clock frequency is changed at the clock replacement time can be reduced as compared with that in the conventional optical disk. This aspect enables the optical disk using CAV system or ZCAV system to be used.
According to a tenth aspect of the invention, there is provided a method according to the eighth aspect, wherein the step of writing in the second management area uses the same revolution rate of the disk as that in writing in the data area in which the defective block exists. Thus, according to the tenth aspect, when the data area and replacement area corresponding to the second management area are located within the same band, it is not necessary to change the revolution rate of the disk at the replacement time.
According to an eleventh aspect of the invention, there is provided a method of recording on an optical disk, comprising the steps of reading a first management area located along the innermost and outermost peripheries of the optical disk that also has a data area and a replacement area provided between the innermost and outermost peripheries, the first management area having stored therein first management information including a recording system of all the disk and second management information including address information of both defective blocks and replacement blocks for replacing the defective blocks; writing certain data in the data area of said optical disk on the basis of the first management information; writing the certain data in the replacement blocks of the replacement area of the optical disk when the defective blocks exist in the data area; writing the second management information associated with the defective blocks and the replacement blocks in a second management area provided between the innermost and outermost peripheries; and copying the second management information written in the second management area into the first management area after the certain data is written in the data area and the replacement area and before the operation of recording on the optical disk is finished, thereby updating the second management information in the first management area. Thus, according to the eleventh aspect, when the starting-up is performed before recording is made in the data area and replacement area, the first management areas located in the innermost and outermost peripheries are accessed for reading, and at the replacement time the second management information is stored in the second management area between the innermost and outermost management peripheries.
According to a twelfth aspect of the invention, there is provided an optical disk according to the first aspect, wherein the data area, the replacement area and the record management area arranged in this order are included between the two other record management areas. Thus, according to the twelfth aspect, when a defective block occur, the optical head is moved in a direction from the data area to replacement area, making a replacement processing, while the head is moved to update the record management area in the same direction.
According to a thirteenth aspect of the invention, there is provided an optical disk according to the second aspect, wherein the second management information further includes information regarding inspection, security, replacement system and/or attribute of the data area. For example, the second management information can include one or a plurality of information items of the presence or absence of surface inspection (certify), kinds of certify, the presence or absence of security flag that allows only a particular user to access, history such as the number of times the user made initialization and attributes such as rewritable type or write once type.
According to a fourteenth aspect of the invention, there is provided an optical disk formatted to have a record management area in which management information can be stored and of which the contents cannot be rewritten by the user, a data area to which the user can make access, and a replacement area capable of providing a replacement block for replacing a defective block that exists in the data area, the record management area being provided at three locations on the optical disk, the three record management areas being capable of storing different contents of the management information according to the locations, a plurality of sets of the data area and the corresponding replacement area adjacent thereto being provided between the two record management areas close to each other. Thus, according to the fourteenth aspect, the defective block present in the data area and replacement block in the replacement area can be located close to each other.
According to a fifteenth aspect of the invention, there is provided a method according to the seventh aspect or eleventh aspect, wherein the second management information further includes information regarding inspection, security, replacement system and/or attribute of the data area. For example, the second management information can include one or a plurality of information of the presence or absence of surface inspection (certify), kinds of surface inspection, the presence or absence of security flag that allows only a particular user to access, history such as the number of times the user made initialization and attributes such as rewritable type or write once type.
Further objects, other features and advantages of the invention will be apparent from the detailed description of the invention taken in conjunction with the accompanying drawings.